Combined motor and compressor



Dec. 4, 1934. Y c. ZORZI 1,983,260

COMBINED MOTOR AND COMPRESSOR Filed April 11, 1950 2 Sheets-Shee 1 4, 'l93 cQ ZORZl COMBINED MOTOR AND COMPRESSOR Filed April '11, 19:50

2 Sheets-Sheet. 2

' IN VEN TOR.

. C484 a 2002/. BY a4;-

' A TTORNEY.

Patented Dec. 4, 1934 UNITED STATES PATENT ornca Application April 11, 1930, Serial Ho. 3,804 In may April 15, 1929 Claims.

This invention relates to a combined electric motor and compressor or pump which may be used for a variety of purposes, such as compressing gases, pumping fiuids or vapors and the like and has for its object the elimination of the usual stuiilng box or gland which must be employed on the compressor shaft when the same is open to the atmosphere.

Another object is to provide a combined mo- 0 tor and compressor in a hermetically sealed casing wherein all sleeves or shields in the air gaps between the rotor and stator of the motor are eliminated.

A further object is to provide a motor com- ,5 pressor unit in a hermetically sealed casing with means for automatically unloading the compressor thereby enabling the unit to be easily started under full load conditions.

Other objects will be apparent from the fol- :0 lowing specification where for the sake of illustration a combined motor and compressor embodying this invention is described as forming the "high side unit of a refrigerating machine.

The complete refrigerating machine may conlli sist of one of these high side units comprising the compressor and motor. The discharge from the compressor is usually carried to a suitable con- I denser where the compressed refrigerant gas is liquefied. The liquid refrigerant is then carried 30 to a suitable expansion valve and on through a suitable evaporator, which in turn is connected to the suction side of the compressor or pump. As this cycle of refrigeration is well understood, it is not here described in detail.

is In many of the systems in common use the only point at which refrigerant can find egress from the frame or where air and moisture may find ingress is around "the shaft of the compressor at which point it is customary to use a stufllng box or gland which causes loss due to friction and which is in danger of leakage from wear with consequent need of adjustment. This stufling box or gland is entirely eliminated by the construction herein described.

In other types of machines the high side consists of the motor and pump enclosed in a hermetically sealed casing but as the motor windings are also enclosed in this casing, it is impos- 50 sible to open the same to repair the windings without danger of losing the refrigerant thereby necessitating recharging of the machine, and when this must be done in isolated locations without the proper apparatus there is great danger of permitting the ingress of air and moisture which prevents the successful operation of the system for any reasonable length of time.

In other constructions where the motor windings are not included within the hermetically sealed casing a steel sleeve has been placed around the rotor, thereby confining the refrigerant to the rotor chamber or cavity. However, when this is done the sleeve forms a path of great magnetic leakage, between the stator and rotor, and considerably impairs the efficiency of the motor as a whole and such construction is relatively expensive. This construction is eliminated by the present invention, as is also the difficulty which occurs when thin steel sleeves are used, of making them sufflciently strong to withstand the pressure of the refrigerant under abnormal working conditions.

In the accompanying drawings:

Figure l is a vertical longitudinal section of a complete high side unit of a refrigerating machine embodying this invention;

Figure 2 is a sectional view on the line a-b-- Figure 1, and t Figure 3 is a detailed view of the fixed eccenrics.

It will be understood that the duct or pipe 10 leads the compressed gases out of the compressor and that the suction pipe 13 takes the gaseous refrigerant into the compressor. The condenser, expansion valve, evaporator, thermostat and motor starting switch constituting the remaining elements of a refrigeration system are all well known and of many types and it is obvious that any suitable arrangement of these may be employed with the improved high side here disclosed. Therefore, the drawings and description have been limited to the high side to which the invention relates. The supporting frame 22 carries both the motor and the compressor and has at its center a laterally extending support 25 in which any suitable type of bearing or bearings may be placed to support the shaft 23 of the rotor 26.

The supporting frame 22 may have attached to it or made integral therewith the feet and is 0 provided with an annular flanged portion adapted to receive the bolts 15.

Surrounding the bearing support 25 is a sleeve generally designated by the numeral 20 consisting of the non-magnetic rings 19 and 21, prefer- 105 ably of metal. The center portion 20a of this sleeve consists of annular stator laminations of suitable magnetic material which are built up and compressed together between the rings 20 and 21.

Thewhole sleeve structure is held together by 110 means of suitable bolts 29 and the sleeve is provided with a'cover 24 so that inside the sleeve and cover is a cavity 36 for the rotor 26. The rotor 26 is mounted upon a shaft 23 which may be supported entirely by one or more hearings in the support 25 or an additional bearing 25a may be placed in the cover 24 thereby supporting the shaft at each side of the rotor, regardless of y form of bearing construction employed. It will be seen that the rotor is hermetically sealed within the cavity 36 except for the opening where the shaft 23 passes outwardly to flywheel 2.

The outer surface of the rotor laminations 20a in sleeve 20 is preferably finished smooth so that the stator laminations 16 having therein suitable slots 17 in which the stator windings 28 are positioned in the usual manner, can be pushed over the sleeve 20 thereby bringing the laminations 16 in the stator in line with the corresponding laminations 20a, in the sleeve 20. As a good pressed fit may be easily secured there is no air gap between the stator and the sleeve and consequently no loss of magnetic flux that would be due to such a gap. I

It will now be seen that the stator windings and the laminations supporting them may be readily removed and replaced without opening the cavity 36 and that this can be done while the machine is in service without releasing any of the refrigerant gas.

If necessary the screws 18 may be removed and the cover 24 taken off thereby obtaining access to the rotor 26.

In order that the motor end of the unit may present a neat appearance a perforated metallic cover 27 may be placed about the stator windings. The perforations in this cover permit the heat from the windings to be readily dissipated and as the windings are outside the cavity 36 into which the refrigerant gas may find its way these windings will not be attacked by the refrigerant and it is easy to provide them with terminals and to connect to them any suitable form of starting switch or other control devices.

Obviously the sleeve 20 can be made to meet the operating requirements of a very wide range of refrigerants and pressures, for the laminations 20a forming part of this sleeve may be made of practically any desired thickness without affecting the operation of the stator windings on the motor. In other words, regardless of the thickness of the annular wall of the sleeve 20 the air gap of the motor is not changed.

In making up the sleeve 20 it is preferable that the bolts 29 be magnetically insulated from the laminations 20a. This is accomplished either by slipping a thin piece of insulating tubing about,

them or by using non-magnetic metal for the bolts and it will also be obvious that the laminations 20a are circular in their plane at right-angles to the shaft 23 and that they may be varnished with a suitable varnish before being tightly compressed by the bolts 29 and that they may be ground inside and outside, thereby obtaining a very accurate fit for the rotor 26 on the inside.

This reduces the air gap to a minimum and also obtains the pressed fit for the stator laminations 16 on the outside, thereby eliminating any air gap whatsoever on the outside surface.

The shaft 23 extends outwardly beyond the frame 22 and carries on its projecting end a flywheel 2 which may be secured to the shaft in any suitable manner. This wheel carries a num- I ber of pivots or pins 1 which carry the cylindrical hollow guides 3. These guides 3 are freely movable upon the pins 1 and carry the free pistons 5.

Each cylinder 6 is formed with a ring portion at right angles to its bore which ring portions fit over eccentrics 12 formed on a bolt which forms or connects with an outwardly projecting duct or pipe 10. This bolt is secured in place by means of nut 11 which fixes it securely to the housing 14 which, in turn, is secured to. the main frame by bolts 15.

It will now be seen that the chamber 35 formed within the housing 14 encloses the flywheel and compressor and that the entire machine including the rotor cavity 36 is hermetically sealed from the atmosphere except for the pressure pipe 10 leading out from the compressor and the suction pipe 13 leading into the casing which is in communication with the cylinders of the compressor as hereinafter described and as these pipes 10 and 13 are connected to the other parts of the refrigerating system, it is evident that the entire system will be hermetically sealed and that the motor-compressor unit will circulate the refrigerant throughout the system without at any time exposing it to the danger of leaking out around the shaft of the compressor.

The eccentrics 12 are so set in relation to the flywheel and pistons that the cylinders operate opposed and are therefore always in balance which aids materially in obtaining quiet running.

Referring to Figure 1 which shows a unit having two cylinders, these are mounted upon two fixed eccentrics, one of which is indicated by the numeral 12, which are made upon the inner end of a hollow bolt 10a which is secured in the housing 14 by means of nut 11 and which may project outwardly or terminate in the pressure duct or pipe 10.

These fixed eccentrics are shown somewhat in detail in Figure 3 and each eccentric has a suction and pressure port. are only shown in one of the eccentrics. The suction port 9 communicates with the chamber 35 via a suitable passage (or slot), and the suction port 32 of the other eccentric communicates with a slot 33 that opens into chamber 35.

For clarity the ports 1 The pressure duct 31 connects with ports in each of the eccentrics, one of which is shown at 8.

Accordingly as the flywheel revolves it will carry with it the cylinders and the hollow cylinder guides 3 and the free pistons 5 will alternately take in (via the hole 7) a charge through one of the suction ports, for instance 32, and then passing over the face of the eccentric thereby closing port 32 this charge will be compressed until port 8 is reached, whereupon the compressed charge will be discharged, via hole '7 and port 8, into duct 31 and into pipe 10. By this arrangement all spring operated valves are eliminated and a smooth even action is obtained.

As the piston 5 is free and floats on the guide 3 it will naturally remain with the cylinder 6 especially if on the suction stroke when the machine stops.

When starting, the free pistons 5 will not begin action until the motor attains a certain speed. Then by reason of centrifugal force they will'go into action. This is entirely different from the action that would take place if these pistons were fixed to the flywheel in any manner.

With this arrangement the machine will readily'start under load and there is no necessity to interpose any automatic unloader or friction clutch between the compressor and motor in order to enable the latter to start.

The cylindrical hollow guides 3 have an inner chamber 3a which has communicating therewith a relief port 4. This arrangement acts as a cushion for the free piston 5 and at the same time the port 4 is so placed as to collect a certain quantity of lubricant in order to not only lubricate the piston but to act also as a cushion while the compressor is in operation.

It will be unde stood that it is customary to place a quantity 0 lubricant in the bottom of the chamber so that the compresor when in operation dips into this lubricant and all of the parts become coated therewith. Some of this lubricant will run down' the inner face of the flywheel and thereby reachthe bearings in the rotor or any other suitable means for oiling these bearings may be used.

While for the sake of illustration a two cylinder compressor has been shown it will be understood that one cylinder or more than two cylinders may be used, by obvious modifications in the disclosure made herein.

I claim:

1. In a motor-compressor unit a compressor and an electric motor having a stator and a rotor, and a gas tight casing enclosing the compressor and the motor rotor, the portion of said casing enclosing said rotor including an annulus of laminations upon which said stator is supported.

2. In a motor-compressor unit comprising a compressor and an electric motor having a stator and a rotor, a shaft connecting the rotor of said motor to the compressor, a gas tight casing enclosing the compressor and the motor rotor, the portion of said casing enclosing said rotor including an annulus of iron laminations upon which said stator is supported, and bearings for 7 said shaft supported within said casing on each side of said annulus.

3. In a motor-compressor unit comprising a compressor and an electric motor having a stator and a rotor, a shaft connecting the motor rotor and the compressor, a gas tight-casing enclosing said compressor and extending between the rotor and the stator to include the rotor and shaft therein, said casing comprising in part annular sections of non-magnetic material separated by an annular section of magnetic material surrounding the motor rotor, and motor stator windings supported by said last annular section.

4. In a motor-compressor unit a compressor and an electric motor having a stator and a rotor, a fluid tight casing forming a chamber enclosing said compressor and the motor rotor, the portion of saidcasing embracing said motor rotor comprising an annulus of iron laminations with nonferrous annular sections on each side of said annulus, a closure plate for one of said sections also forming part of said casing, and bolts for clamping the sections, the annulus and the end plate to the other portion of the casing to complete the sealing thereof.

5. A motor-compressor unit comprising a supporting frame, a sleeve having a rotor cavity therein and formed in part of stator laminations, an electric motor rotor in said cavity, a stator supported outsidesaid sleeve including laminations and a winding removably positioned on said first laminations, a shaft rigidly secured to said rotor projecting from said frame, a compressor supported on said frame, driven by said shaft, said frame and sleeve forming a hermetically sealed casing whereby escape of gas from the compressor is prevented.

' 6. A motor-compressor unit comprising a supporting frame, an annular sleeve forming a rotor cavity and composed in part of stator laminations, an electric motor rotor in said cavity, a shaft for said rotor, a compressor actuated by said shaft, means associated with said sleeve, frame and compressor whereby said rotor cavity and compressor are maintained in fluid-tight relationship and are hermetically sealed from the atmosphere, and an electric motor stator comprising laminations and a winding thereonremovably mounted on said annular sleeve and adapted to be removed therefrom without unsealing said unit.

'1. A motor-compressor unit comprising a supporting frame, an electric motor rotor, a sleeve about said rotor enclosing the same and formed in part of stator laminations, a compressor actuated by said rotor, a cover for said sleeve, and a housing for said compressor, said cover and housing cooperating with said frame to hermetically seal said rotor and compressor from the atmosphere.

8. A motor-compressor unit comprising a supporting frame having a bearing support thereon,

-a shaft in said support, an electric motor rotor on said shaft, .a sleeve enclosing said rotor and cooperating with said frame to enclose said rotor, said sleeve having a portion of its side walls composed of laminations, a stator supported on the outer surface of said sleeve, said stator having laminations in endwise relation and contact with said laminations in .said sleeve, a compressor supported on said frame and operated by said shaft, said frame and sleeve forming a hermetically sealed casing whereby escape of gas from the space about said compressor and motor rotor is prevented.

9. A motor-compressor unit comprising an el ctric motor rotor and compressor, communicating chambers enclosing said rotor and compressor and hermetically sealing saidparts from the atmosphere whereby escape of gas from the space about said compressor and motor rotor is prevented, a wall in the chamber surrounding said rotor comprised in part of an annulose of stator laminations, and a stator including laminations anda winding carried by said first laminations outside said chambers.

10. A motor-compressor comprising a vertical supporting frame having a laterally extending support, an electric motor rotor having a shaft carried by said support, a stator for said rotor, said stator having a portion of its laminations permanently fixed in relation to said rotor and a portion of its laminations removable together with its winding from said rotor without disturbing the same, a housing secured to said frame, and a compressor within said housing connected to said shaft and driven thereby, said frame, housing and fixed laminations constituting parts of a sealed casing whereby escape of gas from the compressor is prevented.

11. A motor-compressor unit comprising a supporting frame, a sleeve supported on one side of said frame and in gas-tight relation thereto, an electric motor rotor within said sleeve, a stator for said rotor carried upon said sleeve, a shaft for said rotor extending through said frame, a

flywheel on the outer end of said shaft, a com- 4 ipaaaeo 12. In a motor-compressor unit, a fluid-tight casing having one portion thereof of substantially larger diameter than the other portion, said last portion adapted to have in its interior an electrical rotor and around its exterior the stator oi an electric motor supported thereby, said first portion having an eccentric shaft secured thereto and a flywheel therein operatively connected to said rotor, a cylinder supported by said shaft, a free piston in said cylinder and a hollow piston guide within said piston and operatively connected to said flywheel, said casings enclosing said rotor, shaft, flywheel, cylinder, piston and hollow piston guide whereby any gas escaping from said cylinder will be confined within said casings and not escape to the atmosphere.

13. A motor-compressor unit comprising a supporting frame having a portion forming a bearing support, an annular flange extending outwardly from said bearing support, a shaft and hearings therefor supported in said bearing support, an electric motor rotor onsaid shaft on one side of said bearing support, a flywheel on the opposite end of said shaft from said rotor and of less diameter than said flange, a compressor operated by said shaft, a housing surrounding said flywheel and compressor secured to said flange,

a casing about said rotor having an annulus of 

